With the development of touch control technologies and mobile terminal technologies, more and more mobile terminals achieve man-machine interactions by means of touch control. At present, touch screens employed by the mobile terminals mainly include capacitive touch screens and resistive touch screens, wherein the capacitive touch screens are popular among more and more people with better definition, light transmittance and touch feeling. The most widely used mobile terminals are mobile phones and tablet computers.
With respect to the capacitive touch screens, touch input operations may be performed by using an active pen instead of a finger, in addition to direct touch operations by using the finger. The principle of the active pen is that the capacitive touch screen receives a signal sent by the active pen via a coupled capacitor. Since the coupled capacitor has an open electrical field, interference signals may be easily coupled, for example display screen interference signals, charger common-mode interference signals and the like. These interference signals may result in a reduction of the signal-to-noise ratio (SNR) of the capacitive touch screen, a decrease of the touch precision and degrade of user experience. Severe interference signals may cause the capacitive touch screen to fail to correctly identify signals sent by a stylus and the like active pens, and thus point jump may be caused.
Therefore, how to improve the signal processing precision of the active pen and improve the signal-to-noise ratio is a technical problem to be urgently solved.